Why FCF is the Gold Standard Metric
FCF is harder to manipulate than earnings because it tracks actual cash movements. Companies can use accounting choices (revenue recognition timing, depreciation methods) to influence reported earnings, but cash either comes in or it doesn't. This is why Warren Buffett and most value investors focus on FCF-based valuations.
For SaaS businesses, FCF matters more than GAAP earnings. High-growth SaaS companies with negative earnings can have strong FCF if they collect annual subscriptions upfront (deferred revenue) and have minimal CapEx. The market prices FCF correctly even when earnings look weak.
Maintenance vs Growth CapEx
Not all CapEx is the same. Maintenance CapEx keeps existing assets operational — it's a true cost of business. Growth CapEx expands capacity and should generate future returns. For FCF analysis, some analysts calculate "owner earnings" (Buffett's term) using only maintenance CapEx as the deduction, arguing growth CapEx is optional investment rather than a required cash cost.
FCF and Valuation
The discounted cash flow (DCF) valuation method prices a business as the present value of all future FCF. FCF yield (FCF / Market Cap) is a common value investor metric: a 5% FCF yield means you're paying 20× FCF, similar to a P/E ratio but using cash rather than accounting earnings.
For SaaS, the "Rule of 40" using FCF margin is increasingly common: Growth Rate + FCF Margin ≥ 40%. Companies exceeding this threshold tend to command premium valuation multiples because they demonstrate both scale and capital efficiency.
15–20%
Target FCF margin for mature SaaS
25–30×
Typical FCF multiple for high-quality SaaS
Rule of 40
Growth % + FCF margin ≥ 40 = premium valuation
< 5%
Typical SaaS CapEx ratio (asset-light)